Snatching a userpic

I'm not sure if this is the right place to ask this, but I'll give it a try. Note: this IS about Livejournal in specific, NOT about OpenID as it might seem at first.

I've just added OpenID support to my website. I have a place for gravatars in my comment list, and I thought it might be cool if, when an LJ user posts a comment using OpenID, it would display their default userpic instead of a gravatar.

So, what I'm currently doing is using CURL to grab http://www.livejournal.com/allpics.bml?user=LJNAME and parse it to extract their default userpic. This is obviously inefficient for both me and LJ (since I'm grabbing that whole page every time, instead of just getting a URL for a userpic) so what I'd like to ask is if there's a simpler way to get the URL to a user's default userpic.

If you want to see what I'm talking about, click here. Haven't gotten it to look quite right in I.E.; cut me some slack :-)